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Merge branch 'master' into feature/simple-example

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Stuart Mitchell 2015-02-26 10:43:13 +13:00
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38
README.md
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@ -8,32 +8,16 @@ y'know. Pretty good.
> -- Terry Pratchett, The Fifth Elephant
## Status
re-frame is still Alpha, not published to clojars [and its use may involve pain](https://github.com/Day8/re-frame/issues/4). But it is close to Beta.
Be sure you use v0.5.0 of reagent.
Todo:
- provide a hook for logging and exception handling
- implement pure event handlers. A macro will be needed.
- continue to use Historian? Or roll our own undo. Only 20 lines of code.
<!--
<img src="http://leiningen.org/img/leiningen.jpg"
alt="Leiningen logo" title="The man himself" align="right" />
-->
## Why Should You Care About re-frame?
Either:
1. You want to develop an app in ClojureScript, and you are looking for a framework; or
2. You believe that by early 2015 ReactJS had effectively won the JavaScript framework wars and
you are curious about the bigger implications. Could it be that the combination of
2. You believe that, by early 2015, ReactJS had won the JavaScript framework wars and
you are curious about the bigger implications. Could the combination of
`reactive programming`, `functional programming` and `immutable data`
**will completely change everything**? If so, what does that look like in a language
that naturally embodies those paradigms?
**completely change everything**? If so, what would that look like in a language
that embraces those paradigms?
## re-frame
@ -631,7 +615,7 @@ So let's now look at how to write and register the subscription handler for `:cu
(reaction (get-in @db [:path :to :a :map cid]))) ;; re-runs each time db changes
;; register our query handler
(register
(register-subs
:customer-query ;; the id (the name of the query()
customer-query) ;; the function which will perform the query
```
@ -691,7 +675,7 @@ Let's sketch out the situation described above ...
The subscription-handler might be written:
```Clojure
(register
(register-subs
:sorted-items ;; the query id (the name of the query)
(fn [db [_]] ;; the handler for the subscription
(reaction
@ -747,7 +731,7 @@ Luckily, we can easily fix that up by tweaking our subscription function so
that it chains `reactions`:
```Clojure
(register
(register-subs
:sorted-items ;; the query id
(fn [db [_]]
(let [items (reaction (get-in @db [:some :path :to :items]))] ;; reaction #1
@ -959,7 +943,7 @@ then to register those handlers with the router.
Here's how we would register our event handler:
```Clojure
(register
(register-pure-handler
:delete-item ;; the event id (name)
handle-delete) ;; the handler function for that event
```
@ -1139,6 +1123,12 @@ To build an app using re-frame, you'll have to:
- write and register event handler functions (control layer and/or state transition layer).
### Licence
Copyright © 2015 Michael Thompson
Distributed under The MIT License (MIT) - See LICENSE.txt
[SPAs]:http://en.wikipedia.org/wiki/Single-page_application
[Reagent]:http://reagent-project.github.io/
[Dan Holmsand]:https://twitter.com/holmsand

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licence.txt Normal file
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@ -0,0 +1,21 @@
The MIT License (MIT)
Copyright (c) 2015 Michael Thompson
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

6
project.clj
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@ -1,7 +1,7 @@
(defproject re-frame "0.1.6"
:description "A reagent framework"
(defproject re-frame "0.1.7"
:description "A Reagent Framework For Writing SPAs, in Clojurescript"
:url "https://github.com/Day8/re-frame.git"
:license {:name "MIT"}
:dependencies [[org.clojure/clojure "1.6.0"]
[org.clojure/clojurescript "0.0-2760"]

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src/re_frame/core.cljs Normal file
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@ -0,0 +1,35 @@
(ns re-frame.core
(:require
[re-frame.handlers :as handlers]
[re-frame.subs :as subs]
[re-frame.middleware :as middleware]))
;; -- API -------
(def register-handler handlers/register)
(def dispatch handlers/dispatch)
(def dispatch-sync handlers/dispatch-sync)
(def register-subs subs/register)
(def subscribe subs/subscribe)
(def pure middleware/pure)
(def undoable middleware/undoable)
(def path middleware/path)
(def validate middleware/validate)
(def log-events middleware/log-events)
(def apply-event middleware/apply-event)
;; -- Convienience API -------
;; virtually ever handler will be pure, make it easy
(defn register-pure-handler
([id handler]
(register-handler id pure handler))
([id middleware handler]
(register-handler id (comp pure middleware) handler)))

10
src/re_frame/handlers.cljs
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@ -22,16 +22,6 @@
(register event-id (middleware handler-fn))))
(defn register
"register a handler for an event"
([event-id handler-fn]
(when (contains? @id->fn event-id)
(warn "re-frame: overwriting an event-handler for: " event-id)) ;; allow it, but warn.
(swap! id->fn assoc event-id handler-fn))
([event-id middleware handler-fn]
(register event-id (middleware handler-fn))))
;; -- The Event Conveyor Belt --------------------------------------------------------------------
;;
;; Moves events from "dispatch" to the router loop.

152
src/re_frame/middleware.cljs
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@ -1,88 +1,102 @@
(ns re-frame.middleware
(:require
[reagent.ratom :refer [IReactiveAtom]]
[re-frame.undo :refer [store-now!]]))
[reagent.ratom :refer [IReactiveAtom]]
[re-frame.undo :refer [store-now!]]
[re-frame.utils :refer [warn]]))
;; -- Middleware Factories -------------------------------------------------------------------------
;;
;; Middleware wraps handlers, providing a composable pipeline. We use middleware so the handlers
;; themselves are kept as simple as possible. In particualr, the handlers can be kept as pure functions.
;;
;; My attempt to explain, by skirting around the hard bits is as follows ...
;;
;; Use "comp" to compose middelware, like this:
;;
;; (def midware (comp undoable pure (validate some-fn))) ;; midware is a function
;;
;; then imagine that we have a pure handler:
;;
;; (defn my-handler
;; [db v]
;; (assoc db :some-key 42))
;;
;; then apply the composed middleare to my-handler:
;;
;; (def h (midware my-handler)) ;; h is "my-handler" wrapped in middleware
;;
;; I could call h like this:
;; (h app-db [:some-key 23]) <---- h is a handler, just pass in 'db' and 'v'
;;
;; Which means, you could just register 'h'
;;
;; (register
;; :some-id
;; h)
;;
;; Middleware factories do your head in initially, because they involve a function, returning a function,
;; returning a function. So I'd suggest you might want to read this explanation
;; (go to "Handlers and Middleware"):
;; http://www.flyingmachinestudios.com/programming/boot-clj/
;;
(defn undoable
"Middleware which stores an undo checkpoint"
[next-handler]
(fn handler
[app-db event-vec]
(store-now!)
(next-handler app-db event-vec)))
;; Read this: https://github.com/Day8/re-frame/wiki/Middleware
(defn pure
"Middleware which allows you to write a pure handler.
1. on the way through it extracts the value in the atom
2. resets the atom with the returned value after calling the handler"
[next-handler]
(fn handler
"Middleware which adapts a pure handler to the non-pure standard calling convention"
[handler]
(fn new-handler
[app-db event-vec]
(assert (satisfies? IReactiveAtom app-db) "re-frame: make-pure not given a Ratom")
(reset! app-db (next-handler @app-db event-vec))))
(assert (satisfies? IReactiveAtom app-db)
(str "re-frame: pure not given a Ratom" (if (map? app-db) ". Perhaps \"pure\" is used twice.")))
(reset! app-db (handler @app-db event-vec))))
;; example of applying
;; warning: untested
(defn undoable
"Middleware which stores an undo checkpoint, prior to handler being called."
[handler]
(fn new-handler
[app-db event-vec]
(store-now!)
(handler app-db event-vec)))
;; warning: untested
(defn apply-event
"Middleware which removes the first bit of v, and \"expands\" other parameters.
Normally handlers get two paramters: db and v.
With this middleware, if v was [:id 1 2], the handler would be called with db, 1, 2.
Use the middleware in the very last place -- right-most in comp"
[handler]
(fn new-handler
[db v]
(apply handler (cons db (rest v)))))
;; warning: untested
(defn path
"Supplies a sub-tree of `app-db` to the handler.
Assumes pure is in the middleware pipeline prior.
Grafts the result back into app-db."
[p]
(fn middleware
[handler]
(fn new-handler
[db v]
(if (satisfies? IReactiveAtom db)
(str "re-frame: \"path\" used in middleware, without prior \"pure\"."))
(if-not (vector? p)
(warn "re-frame: \"path\" expected a vector, got: " v))
(assoc-in db p (handler (get-in db p) v)))))
;; warning: untested
(defn validate
"Middleware that applies a validation function to the db after the handler is finished.
The validation function f, might assoc warnings and errors to the new state, created by the handler.
By validation, I mean validation of what the user has entered, or the state they have taken the app too"
[f]
(fn middleware
[handler]
(fn new-handler
[db v]
(f (handler db v)))))
;; warning: untested
(defn log-events
"Middleware that logs events (vec) using to the given logger fucntion"
[logger]
(fn middleware
[handler]
(fn new-handler
[db v]
(logger v)
(handler db v))))
;; warning: untested
;; check the state of db AFTER the handler has run, using a prismatic Schema.
#_(defn check-schema
"Middleware for checking that a handlers mutations leave the state in a schema-matching way"
[a-prismatic-schema]
(fn middlewear
(fn middleware
[next-handler]
(fn handler
[db v]
(let [val (next-handler db v)
valid? true] ;; XXXXX replace true by code which checks the schema using original parameter
(if (not valid?)
(warn "re-frame: schema not valid after:" ))
val))))
(defn validate
"Middleware that applies a validation function to the db after the handler is finished.
The validation function f, might assoc warnings and errors to the new state, created by the handler.
By validation, I mean validation of what the user has entered, or the state they have taken the app too"
[f]
(fn middlewear
[next-handler]
(fn handler
[db v]
(f (next-handler db v)))))
(warn "re-frame: schema not valid after:" v))
val))))